Excessive Rainfall Possible

By jeffpenner, on May 18th, 2017

Good evening bloggers,

This is Jeff Penner with an update:

We have been tracking two storm systems this week the first one is now in eastern Canada. This was the system from Wednesday, now we are dealing with the second storm system and this is much bigger. So, let’s get into the forecast as it is a complex set up tonight through Friday night.

Here are the locations of the two storm systems as of of Friday evening. There is quite a snowstorm ongoing in Colorado as a very large area of rain and thunderstorms is occurring from Kansas to Texas. The tornado activity has been less that expected, so far, as there have been so many thunderstorms, making for less supercells.

THURSDAY 6 PM: Temperatures ranged from 90° in Dallas to 32° in Casper, WY. What a storm! The warm front extends from the main surface low in the western Oklahoma panhandle to central Illinois. The placement of this warm front will be the key to where the highest tornado threat is located on Friday.

FRIDAY MORNING: The big thunderstorms now in western and central Kansas will roll through our area between 11 PM and 8 AM. These will contain very heavy rain and possibly some damaging winds. These thunderstorms will mess up the surface wind pattern and it looks like the real warm front will get pushed south.

FRIDAY AFTERNOON AND EVENING: This data below suggests the real warm front will stay to the south. This means we have potential for very heavy rain and flash flooding along with large hail and damaging winds with little to no tornado threat. Now, let’s be very careful here. The warm front position is not set in stone and it could easily lift to around I-70 tomorrow evening. If this happens the tornado threat increases tremendously along with the flash flooding threat. We will have to see how this evolves Friday morning.

FRIDAY NIGHT-SATURDAY MORNING: The main storm and cold front will move by and this will end the rain chances early Saturday leading to a decent weekend, regardless of where the warm front sets up Friday afternoon.

RAINFALL FORECAST: This is from the 18z GFS and is quite incredible with total rainfall in the area of 3″ to almost 7″. Is this right? Well, again we have to see how things set up. You can get 2-3″ of rain in one hour with this situation. It is going to depend where the warm front sets up and the track of the thunderstorms. Needless to say, most locations should see 1″ to 3″ of rain, but we will have to be on the look out for locations where it gets excessive and that is why there is a Flash Flood watch in effect through Saturday morning. Remember “TURN AROUND DON’T DROWN.”